The present invention relates generally to aerating tines for use in aerating turf and soil surfaces, and more particularly to a novel aerating tine having improved turf core retention characteristics which assure retention of a turf core as the tine is retracted from the turf or soil during an aerating operation.
It is a common practice in the maintenance and care of turf surfaces, such as residential and commercial lawns and turf surfaces on golf courses and the like, to aerate the turf so as to enable nutrients to more readily hasten root growth, thereby resulting in a more durable and heartier looking turf. Such aeration of turf surfaces is commonly accomplished by aerating machines which employ a plurality of generally tubular tines supported either for rotation on a tine wheel, or for vertical reciprocating movement. In either mode, the tines are caused to undergo substantially longitudinal penetration into and retraction from the turf surface so as to form a pattern of generally cylindrical aeration holes in the turf as the aerating machine traverses the turf surface. Examples of rotary and vertically reciprocating type soil aerating machines are disclosed, respectively, in U.S. Pat. Nos. 4,081,034 and 3,834,464.
The tubular aeration tines employed in turf aerating machines of the aforementioned type are frequently formed with their soil penetrating ends swaged radially inwardly to a smaller diameter than their upper discharge ends. A significant drawback encountered with both straight cylindrical tubular tines and tines having inwardly swaged lower ends is that in certain soils insufficient friction is developed between the tine and a turf or soil core to retain the core within the tine as the tine is retracted from the turf surface. This problem is particularly prevalent in vertically reciprocating tine type aerators and frequently results in a portion or all of the turf core being left on the ground. This is particularly undesirable when the turf surface comprises a play surface such as a golf green or the like. It has been found that on golf courses, recent advances in cultural practices have made it more difficult to extract cores from the turf using conventional tines. A need thus exists for a tubular turf aerating tine which achieves sufficient friction between the tine and a turf or soil core to ensure retention of the core within the tine during retraction from the turf surface, while enabling the retained core to be readily pushed axially outwardly from the discharge end of the tine by a core formed during a subsequent turf penetration.